SIMULATION - There are two different networks, 192.168.0.0/24 and 192.168.1.0/24. Your System is in 192.168.0.0/24 Network. One RHEL6 Installed System is going to use as a Router. All required configuration is already done on Linux Server. Where 192.168.0.254 and 192.168.1.254 IP Address are assigned on that Server. How will make successfully ping to 192.168.1.0/24 Network`s Host? 

See explanation below.

vi /etc/sysconfig/network GATEWAY=192.168.0.254 OR - vi /etc/sysconf/network-scripts/ifcfg-eth0 DEVICE=eth0 BOOTPROTO=static - ONBOOT=yes - IPADDR=192.168.0.? NETMASK=255.255.255.0 - GATEWAY=192.168.0.254 - service network restart Gateway defines the way to exit the packets. According to question System working as a router for two networks have IP Address 192.168.0.254 and 192.168.1.254.